maeqtt/mqtt/packets/packets.go
2021-09-01 22:36:43 +02:00

82 lines
1.9 KiB
Go

package packets
import (
"bufio"
"bytes"
"fmt"
"io"
"badat.dev/maeqtt/v2/mqtt/types"
)
type PacketVisitor interface {
visitConnect(ConnectPacket)
visitPublish(PublishPacket)
visitDisconnect(DisconnectPacket)
}
type ClientPacket interface {
visit(PacketVisitor)
}
type ServerPacket interface {
Encode() (bytes.Buffer, error)
}
type PacketType byte
const (
PacketTypeReserved PacketType = 0 // Forbidden
PacketTypeConnect = 1
PacketTypeConnack = 2
PacketTypePublish = 3
PacketTypePuback = 4
PacketTypePubrec = 5
PacketTypePubrel = 6
PacketTypePubcomp = 7
PacketTypeSubscribe = 8
PacketTypeSuback = 9
PacketTypeUnsubscribe = 10
PacketTypeUnsuback = 11
PacketTypePingreq = 12
PacketTypePingresp = 13
PacketTypeDisconnect = 14
PacketTypeAuth = 15
)
func ReadPacket(r *bufio.Reader) (*ClientPacket, error) {
println("AAAA")
fixedHeader, err := r.ReadByte()
if err != nil {
return nil, err
}
println("BBB")
highestFourBits := uint((fixedHeader >> 4) & 0b1111)
lowerFourBits := uint(fixedHeader & 0b1111)
dataLength, err := types.DecodeVariableByteInt(r)
if err != nil {
return nil, err
}
reader := io.LimitReader(r, int64(dataLength))
control := controlPacket{
packetType: PacketType(highestFourBits),
flags: lowerFourBits,
reader: reader,
}
var packet ClientPacket
switch control.packetType {
case PacketTypeConnect:
packet, err = parseConnectPacket(control)
case PacketTypePublish:
packet, err = parsePublishPacket(control)
case PacketTypeDisconnect:
packet, err = parseDisconnectPacket(control)
default:
return nil, fmt.Errorf("Unknown packet type %v", control.packetType)
}
return &packet, err
}